• Browse
    • Author
    • Year
    • Platform
    • Organizations
    • Programs
    • Research Networks
    • Type
  • Search
    • Simple
    • Advanced
  • About
    • About
    • Policies
    • Citation Guide
  • Login
    Logo Alfred Wegener Institut
    Logo Alfred Wegener Institut
    Alfred-Wegener-Institut
    Helmholtz-Zentrum für Polar-
    und Meeresforschung
    • Imprint
    • Contact
    • OAI
    • RSS 2.0

    EPIC.awi.de

    Home
    • Browse
      • Author
      • Year
      • Platform
      • Organizations
      • Programs
      • Research Networks
      • Type
    • Search
      • Simple
      • Advanced
    • About
      • About
      • Policies
      • Citation Guide
    • Login
      Login

      On the impact of impurities on the densification of polar firn

      Edit Item Edit Item

      General Information:

      Citation:
      Hörhold, M. , Laepple, T. , Freitag, J. , Bigler, M. , Fischer, H. and Kipfstuhl, S. (2012): On the impact of impurities on the densification of polar firn , Earth and Planetary Science Letters, 325-32 , pp. 93-99 . doi: 10.1016/j.epsl.2011.12.022
      Cite this page as:
      hdl:10013/epic.41153
      DOI:
      https://doi.org/10.1016/j.epsl.2011.12.022
      Contact Email:
      maria.hoerhold@awi.de
      Related Data:

      Download:

      [img]
      Preview
      PDF
      ImpactImpurties.pdf

      Download (1MB) | Preview
      Cite this document as:
      hdl:10013/epic.41153.d001
      Abstract:

      Understanding polar firn densification is crucial for reconstructing the age of greenhouse gas concentrations extracted from ice cores, and for the interpretation of air in ice as a dating tool or as a climate proxy. Firn densification is generally modeled as a steady burial and sintering process of defined layers, where the structure of the layering is maintained along the whole firn and ice column. However, available high-resolution density data, as well as firn air samples, question this picture and point to a lack of understanding of firn densification. Based on analysis of high-resolution density and calcium concentration records from Antarctic and Greenland ice cores, we show for the first time that also impurities may have a significant impact on the densification. Analysis of firn cores shows a correlation between density and the calcium ion (Ca++) concentration, and this correlation increases with depth. The existence of this relationship is independent of the local climatic conditions at the core sites analyzed. The strong positive correlation between the density and the logarithm of Ca++ concentration indicates that impurities induce softening and lead to faster densification over a wide range of concentrations. In one core, the impurity effect manifests itself so strongly that the density develops a seasonal cycle closely following the seasonal cycle of Ca++. Our results clearly show that the structure of the firn layering changes with depth and suggest that the increased variability in density observed in deep firn, recently described as a universal feature of polar firn, may arise from the influence of Ca++ and/or other impurities. The impurity effect is likely to have direct implications on our understanding of glacial firn densification and on glacial gas age estimates.

      Further Details:

      Item Type:
      Article
      Authors:
      Hörhold, Maria ; Laepple, Thomas ; Freitag, Johannes ; Bigler, Matthias ; Fischer, Hubertus ; Kipfstuhl, Sepp
      Divisions:
      AWI Organizations > Geosciences > Glaciology
      AWI Organizations > Climate Sciences > Paleo-climate Dynamics
      Programs:
      Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 1: The Changing Arctic and Antarctic > WP 1.1: Role of Ice Sheets in the Earth System
      Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.1: Past Polar Climate and inter-hemispheric Coupling
      Eprint ID:
      32560
      Logo Alfred Wegener Institut
      Alfred-Wegener-Institut
      Helmholtz-Zentrum für Polar-
      und Meeresforschung
      Logo Helmholtz

      • Browse
        • Author
        • Year
        • Platform
        • Organizations
        • Programs
        • Research Networks
        • Type
      • Search
        • Simple
        • Advanced
      • About
        • About
        • Policies
        • Citation Guide
      • Imprint
      • Contact
      • OAI
      © Alfred-Wegener-Institut